The aging process and its concomitant health issues in relation to the complex interplay of protein, carbohydrate, and fat metabolism represent strong research initiatives at the University of Arkansas for Medical Sciences (UAMS). These metabolic changes are related to the loss of body weight, specifically loss of skeletal muscle mass and skeletal and cardiac muscle functional capabilities. In conjunction with the Center for Translational Research in Aging & Longevity (CTRAL) at the Donald W. Reynolds Institute on Aging at UAMS, the proposed Nutrition, Metabolism, and Physiology Core has a unique ability to perform innovative, well-controlled studies in elderly human and rodents regarding the influence of specific therapeutic measures on changes in body weight and skeletal and cardiac muscle function during aging and disease as well as on other metabolic and physiologic endpoints. This Core is essential to assess the clinical and functional consequences of these therapeutic measures. To maximize the interpretative value of our studies, this Core will interface directly with the other cores to form a comprehensive resource to establish efficacy of nutrient supplementation or other intervention studies in the elderly. A centralized facility devoted to Nutrition, Metabolism, and Physiology research will provide an efficient mechanism for interaction among investigators interested in aging research and will enhance economically efficient utilization of resources. Clinical assessment tools will allow us to evaluate many different domains of body composition. Standardized tests will allow us to evaluate function on every level, and metabolic kitchen facilities will enable us to support nutritional interventions and diets. The CTRAL and the Core facilities are housed at the Institute on Aging on the UAMS campus. The goal of this Core is to provide a platform for collaboration for investigators who are interested in aging research and want to study aspects of nutrition, metabolism, and physiology in relation to aging. In this manner, the Core will facilitate investigations. A significant number of NIH-funded investigators are already involved in aging-related translational research, and the Core will facilitate continual growth and development in this area.